The present invention relates to libraries and more particularly, to libraries for accommodating cartridges accommodating storage media.
Libraries for accommodating storage media to be loaded in personal computers or the like are subject to stringent dimensional restrictions. This dictates appropriate methods of accommodating cartridges. A variety of libraries thus have heretofore been proposed and used.
FIGS. 7 and 8 show an example of such library, which is disclosed in Japanese Patent Disclosure No. 1-285056. This library has a path 102 provided centrally of a housing 101. A cartridge transfer mechanism 103 is provided for movement along the path 102. The library further comprises a drive unit 105 facing the path 102 and storage units 106 to 109 disposed in four rows A to D on the opposite sides of the path 102.
The rows A to D consist of pluralities of storage units 106 to 109, respectively. In each of these rows, a space corresponding to one storage unit, as shown by dashed rectangle in FIG. 7, is provided so that the storage units are movable along the row. The storage units 106 to 109 are supported on guide rails 111 and 112 supported in the housing 101, and are movable only horizontally along the rails via coupling members 113 and 114 mounted on them. That is, the storage units 106 to 109 are movable along a rack 112a mounted on the rail 112a by prime motors 115 provided therein and each having a pinion 115a meshing with the rack 112a.
In operation, for the transfer of a cartridge 110 from the storage unit 107 or 108 to the drive unit 105, the cartridge transfer mechanism 103 takes out the given cartridge 110 from the storage unit 107 (or 108). The taken out cartridge 110 is conveyed and then inserted into the drive unit 105. For the transfer of a cartridge 110 from the storage unit 106 or 109 to the drive unit 105, the storage unit 107 or 108 located ahead of the storage unit 106 (or 109) with the given cartridge 110 stored therein, is moved to a position able to be accessed by the cartridge transfer mechanism 103. Then, the cartridge transfer mechanism 103 can take out the cartridge 110 and, like the above case, insert the same into the drive unit 105.
The above prior art library, however, has a problem that the spaces necessary for moving the storage units deteriorate the accommodation efficiency. In addition, a prime drive source is necessary for each storage unit, and each storage unit should be positioned at a predetermined position. Furthermore, flexible cables are necessary for transmitting signals from sensors to a control unit. For the above reasons, the whole mechanism is relatively complicated, and also a large number of necessary drive sources dictate a large number of parts, thus leading to high cost. Still further, for increasing the access speed the storage units should be moved at a time. In this case, however, collision of storage units are possible unless all the storage units are moved at a constant speed. In the long run, the storage units have to be moved one by one, leading to access time increase. Moreover, spaces corresponding to at least two storage units are necessary, and the width of the library is correspondingly increased.